Sorry; I struggled to follow the instructions on how to do a backtrace.

Here's the full log from trying to view the calendar in the SOGo web ui:

Mar 11 13:32:18 sogod [1000]: |SOGo| starting method 'GET' on uri '/SOGo/so/neil@example.com/Calendar/eventsblocks?ed=20240331&sd=20240226&view=monthview'
2024-03-11 13:32:18.699 sogod[1000:1000] <MySQL4Channel[0x0x55d368254b80] connection=0x0x55d368252970> SQL: SELECT c_path4 FROM sogo_folder_info WHERE c_path2 = 'neil@example.com' AND c_folder_type = 'Appointment';
2024-03-11 13:32:18.700 sogod[1000:1000] <MySQL4Channel[0x0x55d368254b80] connection=0x0x55d368252970>   query has results, entering fetch-mode.
2024-03-11 13:32:18.703 sogod[1000:1000] <MySQL4Channel[0x0x55d368254b80] connection=0x0x55d368252970> SQL: SELECT b.c_name,b.c_content,b.c_creationdate,b.c_lastmodified,b.c_version,a.c_component,a.c_title,a.c_location,a.c_orgmail,a.c_status,a.c_category,a.c_classification,a.c_isallday,a.c_isopaque,a.c_participants,a.c_partmails,a.c_partstates,a.c_sequence,a.c_priority,a.c_cycleinfo,a.c_iscycle,a.c_nextalarm,a.c_description,a.c_uid,a.c_startdate,a.c_enddate FROM sogo_quick_appointment a, sogo_store b WHERE (a.c_folder_id = 16 AND b.c_folder_id = 16) AND ((c_component = 'vevent') AND ((c_startdate IS NULL) OR (c_startdate <= 1711925999)) AND ((c_enddate IS NULL) OR (c_enddate >= 1708905600)) AND (c_iscycle = 0)) AND a.c_name = b.c_name AND (c_deleted != 1 OR c_deleted IS NULL);
2024-03-11 13:32:18.712 sogod[1000:1000] <MySQL4Channel[0x0x55d368254b80] connection=0x0x55d368252970>   query has results, entering fetch-mode.
2024-03-11 13:32:18.714 sogod[1000:1000] <MySQL4Channel[0x0x55d368254b80] connection=0x0x55d368252970> SQL: SELECT b.c_name,b.c_content,b.c_creationdate,b.c_lastmodified,b.c_version,a.c_component,a.c_title,a.c_location,a.c_orgmail,a.c_status,a.c_category,a.c_classification,a.c_isallday,a.c_isopaque,a.c_participants,a.c_partmails,a.c_partstates,a.c_sequence,a.c_priority,a.c_cycleinfo,a.c_iscycle,a.c_nextalarm,a.c_description,a.c_uid,a.c_startdate,a.c_enddate FROM sogo_quick_appointment a, sogo_store b WHERE (a.c_folder_id = 16 AND b.c_folder_id = 16) AND ((c_component = 'vevent') AND ((c_startdate IS NULL) OR (c_startdate <= 1711925999)) AND ((c_cycleenddate IS NULL) OR (c_cycleenddate >= 1708905600)) AND (c_iscycle = 1)) AND a.c_name = b.c_name AND (c_deleted != 1 OR c_deleted IS NULL);
2024-03-11 13:32:18.716 sogod[1000:1000] <MySQL4Channel[0x0x55d368254b80] connection=0x0x55d368252970>   query has results, entering fetch-mode.
2024-03-11 13:32:18.726 sogod[1000:1000] EXCEPTION: <NSException: 0x55d3687c5070> NAME:NSInvalidArgumentException REASON:NSDataMalloc(instance) does not recognize propertyList INFO:(null)